Stereolithographic supports

Abstract

An improved stereolithographic process for forming three-dimensional objects using an improved support structure and the improved support structure is described. The support structure is formed by using differential curing of the liquid media material to form solid supports with weak points at selected locations to facilitate support removal from a three-dimensional object and minimize post-processing.

Having thus described the invention, what is claimed is:  
     
       1. A stereolithographic part formed by selective stimulation of a liquid medium to a solid state comprising: 
       (a) at least one support structure with an intermediate region connecting opposing interfacing regions, the interfacing regions contacting the part at interfacing boundaries;  
       (b) the intermediate region having a first solid cure depth; and  
       (c) the interfacing regions having a second solid cure depth, the second solid cure depth being sufficiently less than the first solid cure depth to create weak points where the support structure is easily separable from the part.  
     
     
       2. The part according to  claim 1  wherein the interfacing regions further comprise up-facing interfacing regions and down-facing interfacing regions. 
     
     
       3. The part according to  claim 2  wherein the part has a third solid cure depth greater than the second solid cure depth. 
     
     
       4. The part according to  claim 3  wherein the support structure further comprises vertically oriented strands. 
     
     
       5. The part according to  claim 4  wherein the strands each have the opposing interfacing regions connected to an object interfacing side. 
     
     
       6. The part according to  claim 5  wherein the strands each have an object non-interfacing side orthogonally intersecting the object interfacing side. 
     
     
       7. The part according to  claim 6  wherein adjacent vertically oriented strands are connected and reinforced with at least one projection extending therebetween. 
     
     
       8. The part according to  claim 5  wherein the object non-interfacing side and the object intersecting side are graphically patterned triangles. 
     
     
       9. The part according to  claim 2  wherein the support structure is reinforced with triangular braces. 
     
     
       10. The part according to  claim 1  wherein the support structure to reinforce the part includes gussets. 
     
     
       11. The part according to  claim 10  wherein the gussets are formed from horizontal strips and angular strips connected to the part, the strips being separated by spaces to facilitate drainage of the liquid medium during part generation.